1. Field of the Invention
This invention relates generally to outdoor construction apparatuses, and more particularly to apparatuses adapted to reduce rotting of joists due to moisture trapped between the supporting end of a joist and a supported material.
2. Background of the Invention
Outdoor structures, such as decks, gazebos etc., are subject to the harsh environment generated by mother nature including heat, humidity, and rain. Decks, for example, are typically constructed of a supporting structure formed of spaced joists or stringers which support decking extending transverse to the end of the joist supporting the decking. The supported decking is typically secured to the joist using standard fasteners, such as nails or screws, to obtain a sound structure.
While the exposed decking material can be protected from the weather by treating, such as by staining and water sealing with commercially available products, the joists are typically comprised of treated lumber to achieve a structure with a satisfactory useful life. However, even joists comprised of treated lumber eventually rot due to the moisture which becomes entrapped between the joist and the supported decking. Even though the ends of the joists are usually not directly exposed to the atmosphere, the porous properties of wood act as a wick and pull moisture from rain or condensation under the decking and facilitates rotting.
Prior art apparatuses are known to prevent moisture and humidity from rising beneath flooring of indoor structures, and which may be disposed between joists and the flooring for cushioning the surfaces against one another, and to achieve a dampening of sound.
U.S. Pat. No. Re. 18,573 teaches a sound deadening device comprising a felt strip located between a furring strip and the top layer of the floor. However, the felt strip is not water impermeable and would not reduce joist rot, nor is taught to be disposed over a joist between the joist and a surface which is subjected to the outdoor environment.
U.S. Pat. No. 3,385,018 to Harry teaches a support member dimensioned to conform to corrugated panels to be used for walls, roofs etc. Disposed between each corrugated panel and each support member is an elastomeric, ribbon-like winged filler strip of flexible, relatively dense material. The filler strip is directed towards cushioning to surfaces against one another, and is not adapted to prevent moisture from becoming entrapped between the support member and the panels.
U.S. Pat. No. 3,180,460 to Liskey, Jr. teaches a cushion strip upon which floor panels rest. The strips cushion the panels and seal the marginal portions of the floor panels against leakage of air or seepage of dust therebetween. This device, however, is not adapted to prevent damage due to moisture generated from above the joists.
U.S. Pat. No. 4,879,856 to Jones et al., teaches a floor system designed to be placed over an undersized joist in order to provide some additional stability for the support member. Since the structure taught in Jones is primarily designed for interior use, it would be only marginally effective for reducing water damage to the top of the joist.